revert changes to build

Author: l-trotta

build.gradle.kts

@@ -19,8 +19,9 @@
 
 allprojects {
     group = "co.elastic.clients"
-    version = (File(project.rootDir, "config/version.txt").readText().trim() + "-SNAPSHOT")
-
+    // Release manager provides a $VERSION. If not present, it's a local or CI snapshot build.
+    version = System.getenv("VERSION") ?:
+            (File(project.rootDir, "config/version.txt").readText().trim() + "-SNAPSHOT")
     repositories {
         maven {
             name = "Elastic-Snapshots"